CHICAGO — If ever Carol Gaetjens becomes unconscious with no hope of awakening, even if she could live for years in that state, she says she wants her loved ones to discontinue all forms of artificial life support.

But now there’s a catch for this churchgoing Catholic woman. U.S. bishops have decided that it is not permissible to remove a feeding tube from someone who is unconscious but not dying except in a few circumstances.

People in a persistent vegetative state must be given food and water indefinitely by natural or artificial means as long as they are otherwise healthy, the bishops say. The new directive, which is more definitive than previous church teachings, also appears to apply broadly to any patient with a chronic illness who has lost the ability to eat or drink, including victims of strokes and people with advanced dementia.

Catholic medical institutions are bound to honor the bishops’ directive issued late last year, as they do church teachings on abortion and birth control. Officials are weighing how to interpret the guideline in various circumstances.

What happens, for example, if a patient’s advance directive, which expresses that individual’s end-of-life wishes, conflicts with a Catholic medical center’s religious obligations?

“Every case is individual, and each person’s needs must be met,” said Sister Mary Norberta, president and CEO of St. Joseph Healthcare in Bangor. “Certainly, advance directives have always had a very high standing.”

Sister Norberta said the new guidance from the bishops is unlikely to change the way treatment is decided and care is given at St. Joseph Hospital, one of three hospitals in Maine directly affiliated with the Catholic Church. Neither will it affect care provided through St. Joseph Home Care and Hospice, she said, where patients with terminal conditions often request to be allowed to die comfortably at home without interventions such as tubes for feeding or hydration.

Gaetjens, 65, said she did not know of the bishops’ position until recently and finds it difficult to accept.

“It seems very authoritarian,” said the Evanston, Ill., resident. “I believe people’s autonomy to make decisions about their own health care should be respected.”

The guideline addresses the cases of people like Terri Schiavo, a Catholic woman who lived in a persistent vegetative state for 15 years without consciousness of her surroundings. In a case that inspired a national uproar, Schiavo died five years ago after her husband won a court battle to have her feeding tube removed over the objections of her parents.

The directive’s goal is to respect human life, but some bioethicists are skeptical.

“I think many [people] will have difficulty understanding how prolonging the life of someone in a persistent or permanent vegetative state respects the patient’s dignity,” said Dr. Joel Frader, head of academic pediatrics at Children’s Memorial Hospital in Chicago and professor of medical humanities at Northwestern University’s Feinberg School of Medicine.

Gaetjens, a hospice volunteer and instructor at Northwestern University, has thought long and hard about illness and the meaning of life after struggling with multiple sclerosis for 40 years.

She said she has told her sister and a close friend that she does not want “heroic measures” undertaken on her behalf at the end of life. But she acknowledged that she has not studied Catholic teachings on the subject or thought through all the implications of her position.

“My pleasure is in being part of the human race,” she said. “If that’s gone, if I can’t interact with other people, even if they could give me nutrition and keep me hydrated, I’m not interested in being preserved.”

Some experts are advising that a similar stance is no longer tenable for devout Catholics. Church members should steer away from advance directives that make blanket statements such as “I don’t want any tubes or lifesaving measures,” said the Rev. Tadeusz Pacholczyk, director of education for the National Catholic Bioethics Center in Philadelphia.

The church’s view is that giving food and water to a person through a feeding tube is not a medical intervention but basic care, akin to keeping the patient clean and turning him to prevent bedsores, Pacholczyk said.

Pope John Paul II articulated the principle in a 2004 speech, and the Congregation for the Doctrine of the Faith, an arm of the Vatican, expanded on it in a 2007 statement. The new guideline incorporates those positions in Directive 58 of the U.S. bishops’ Ethical and Religious Directives for Catholic Health Care Services.

There are several important exceptions. For one, if a person is actively dying of an underlying medical condition, such as advanced diabetes or cancer, inserting a feeding tube is not required.

“When a patient is drawing close to death from an underlying progressive and fatal condition, sometimes measures that provide artificial nutrition and hydration become excessively burdensome,” said Erica Laethem, a director of clinical ethics at Resurrection Health Care, Chicago’s largest Catholic health care system.

Some ethicists are interpreting that exception strictly. The Rev. William Grogan, a key health care adviser to Cardinal Francis George and an ethicist at Provena Health, based in Mokena, Ill., said death must be expected in no more than two weeks — about the time it would take someone deprived of food and water to die.

But Joseph Piccione, senior vice president of mission and ethics at OSF Health Care in Peoria, Ill., said that if a patient knows she is dying of, say, incurable metastasized ovarian cancer but is several months from death, she can decline to have a feeding tube inserted if she anticipates significant physical or emotional distress from doing so.

A second exception has to do with bodily discomfort. If infection develops repeatedly at the site of the feeding tube, for instance, artificial nutrition and hydration can be refused or discontinued, Catholic ethicists agree.

A third exception is allowed when inserting or maintaining a feeding tube becomes “excessively burdensome” for a patient. That would apply, for instance, if a person regurgitates the food and develops pneumonia when it enters the lungs, Grogan said.

“Decisions are made case by case,” and that will continue, said Ron Hamel, senior director of ethics at the Catholic Health Association of the United States.

Of particular concern is whether Catholic medical centers will honor an advance directive stating broadly that a person does not want a feeding tube inserted.

Compassion & Choices, a group that supports the right of dying people to end their lives, suggested the potential for conflict is significant.

“Now, [Catholic] hospitals and nursing homes have no choice but to enforce Catholic doctrine universally over patient wishes,” the group’s president, Barbara Coombs Lee, wrote on her blog.

But most ethicists said they do not see a significant problem. Disagreements, they say, usually can be resolved by discussing people’s end-of-life concerns, such as fear of being abandoned, fear of living in pain or fear of becoming entirely dependent on others.

It is rare for people to be very specific about their wishes.

“I have never seen an advance directive that says, ‘If I am in a persistent vegetative state, I ask that you withdraw food and water,’ “ Laethem said.

“We will be very attentive to patients’ advance-care planning,” Piccione said.

That offers some solace to people like Jim Lindholm, 69, who is struggling with a recurrence of non-Hodgkin’s lymphoma and attends St. Nicholas Catholic Church in Evanston.

“If there is no hope of recovery for me, if I’ve lost my active mental life, I don’t see any reason to keep my body alive,” he said. “I would prefer to die a peaceful death.”

Lindholm speaks from deep personal experience. A dozen years ago, his father suffered a stroke and lost the ability to feed himself and speak for himself. Attempts to feed him by hand did not succeed. His advance directive was clear: no extraordinary measures.

Lindholm still struggles with it. Did his father really want to starve to death? If his mother had agreed to the feeding tube, how long might he have lived?

“We owe it to those who survive us to make it very, very clear what we mean by ‘do not resuscitate,’” Lindholm said.

At St. Joseph Healthcare in Bangor, Sister Norberta said she wishes everyone would make an advance directive to guide physicians and family members in deciding the appropriate end-of-life care. People should also make out wills, plan funeral arrangements and keep their financial affairs in order, she said.

“Every one of us has a limited lifetime,” she said, “but we seem to want to escape thinking about that in our society.”

Although medical institutions are legally bound to respect patients’ advance directives, exceptions exist for providers who object by reason of conscience or religious belief, said Charles Sabatino, head of the American Bar Association’s Commission on Law and Aging.

The bishops’ guidelines specify that “advance directives are to be followed, so long as they do not contradict Catholic teachings,” said John Haas, president of the National Catholic Bioethics Center. How those teachings will be interpreted has yet to be resolved.